Correct height of block studs?

[valerea]

Hi
I am rebuilding my 4.2 and replacing the block studs. The machine shop said they tapped out the studs when the bock was machined. However, even though the studs go in freely they are not a uniform height. The 4 with lifting brackets will be longer I suspect but is there a uniform height. I darent over tighten them for obvious reasons

Thanks in anticipation

Paul

[abowie]

Short stud or long stud block?

[valerea]

Long stud

[Gfhug]

Paul, if you include you car series and type (FHC, OTS, 2+2) in your signature it will often be quicker for people to respond to your enquiries. Just helps the process.

I've done a quick search and I know there will be others who will know this information but one of the things to make sure the studs are properly home is to screw them in by the correct number of turns, this ensures they are truly in and not bottoming out on silt, etc. I hope this will help you.

Geoff

[valerea]

Thanks for that

It is a 66 roadster. 4.2 with replaced block (69) 5 core plug, long stud

I have all usual manuals, Haynes, Bentley auto books etc but no reference to depth or turns

[abowie]

The likelihood is that the threads at the bottom of the holes in the block still have some crap in them.

We have a zero taper tap brazed onto a long rod that we use to clean them. It's just a matter of repeatedly passing the tap, blowing out the threads, scraping out the bottom of the hole with a screwdriver or similar and then inspecting it until it's really clean. This can take a while.

[Gfhug]

At a seminar on the XK engines we were told that the studs need 17 1/4 to 17 1/2 turns to fully screw in.
If you are not getting that many then the holes are still not cleaned out fully. Do as Andrew says regarding cleaning out.

Geoff

[valerea]

Many thanks. I have been scraping the bottom of the chamber and yes crud is coming out

This leads me to another question in terms of how/when to flush the block out. The machine shop did say that they cleared a lot of rubbish but there. Is clearly residue left

Most helpful

Paul

[mgcjag]

Hi Paul if the engine is out of the car then with water pump and plate on rear of engine below head removed and drain plug you have good access to jet wash.... Steve

[abowie]

The machine shop did say that they cleared a lot of rubbish but there. Is clearly residue left

It is a frustrating job, not the least because it is hard to see the bottom of the stud holes. You just have to persevere.

Our machinist hot tanks the blocks and then sandblasts the water galleries. It is astonishing how much scale and casting sand comes out of some of them.